DupliFrames creating too few objects
Ohh, found out.
Under the "Duplication"->"Frame" option in my object settings, I had "End" set to 100. Size it up and more objects were created.

EDIT:
Apparently: If you set "End" to let's say 800, then 800 objects will be created no matter how many frames you've set up under "Path animation". So if under "Path animation"(in your curve settings) you've set "frames" to 600, Blender will still create 800 objects. The 200 extra objects will be put in the same place as the 600-th - in other words, at the last position.